Replacing an odd sized front door mortice lock.

[elmag28]

Hi,
I will be grateful for your help in trying to replace an old front door mortice lock.
There are no markings on the lock & it measures 149mm/ 6 inches but the bracket is about 40 mm.
Ones I can see online have a backset if around 51-52 mm.
I am attaching the pictures of the lock with measurements & will be grateful for any ideas on trying to replace it.
Many thanks.

 

[blup]

Chubb/ union do them but you might need to chop out the rebate etc.

(Ex Chubb) Union 3G115 Non British Standard 5 Lever Mortice Deadlock

Union C-Series 3G115 5 Lever Non-British Standard Mortice Deadlock. The 3G115 locks are Force resistant, Anti-pick and with Anti-saw security features. These deadlocks are non handed and are designed for wooden doors.

www.lockshopdirect.co.uk

 

[JohnD]

It is a 6-inch Victorian Horizontal Sashlock

I used to have a house (actually Edwardian) with those, and am very fond of them. I bought some for restoration (not quite as old) from the warehouse clearance of a old London family business, though I think mine are five-inch. Modern replicas are still made for restorers.

If I have spare time, I will look and see what I have.

The 3G115 is not the correct replacement.

Your lock is clearly made to Imperial measurements, the case is six inch and the knob backset is four inch. I can't make out the keyhole backset, it will be to a quarter-inch or possibly an eighth.

There is a Chubb lock that is much better quality, and incredibly expensive retail, but is suitable for the front or external door of a church or other grand old building. It is thicker and generally bigger and more heavily built than the simple "bedroom door" lock in your pics. I have one on one of my doors. It is the 3J60

 

[JohnD]

P.s.

If you goggle for "Horizontal Sashlock" you will find ads, mostly for modern replicas. Three lever is adequate for internal locks, and much more secure than your old one, which is warded and probably has just one tumbler. You might need to shave out the mortice as they are a bit thicker. Check the measurements before purchase. There may be slight differences in heyhole and knob spindle position.

It is important to know that because the mortice is so large, they will weaken the door, and are unsuitable for most doors. They must not be fitted at the rail height of most panelled doors (where they look best) because you would cut away the tenon that holds the door together.

They can be fitted in some fire doors that are thick and made of monolithic pressed chipboard or other material with no tenons. I do not know if this would remove their fire rating.

 

[JohnD]

P.s.

I also have some horizontal sash latches. The same size but they take a knob spindle only, there is no keyhole or locking action.

Note that these locks should have knobs, never lever doorhandles. Some older styles have a T handle.

 

[JohnD]

I just measured some of my stock

I have 6 inch cases, with 5 inch backset to knob spindle and 2 inch to keyhole

Modern replacements with 100mm knob and about 44mm to keyhole

Some others are in a crate somewhere, I think they are Legge.

 

[JohnD]

I think this one (with 5 inch case) might suit. Look at the dimensioned drawing.

I may have some at a better price.

Imperial G5011/G5012 Horizontal Non British Standard 5 Lever Mortice Sashlock

These Imperial G5011/G5012 mortice sashlocks are 5 lever mortice locks, available with a case depth of 5 inches / 127mm or 6 inches / 150mm The latch is operated by a lever handle on either side, the deadbolt is operated by a key from either side. Pierced to accept 38mm bolt through furniture. The

www.lockshopdirect.co.uk

 

[JohnD]

A cheaper alternative would be to fit a modern BS deadlock with a keyhole backset close to existing

And a long Tubular Mortice Latch above, with the knob, in a new hole

Probably glue and pin a wooden block in the back of the existing mortice to add a little strength

Tubular latches are easy to get and install

The yellow-cased Altro brand have a very nice action and seem solidly built

https://www.ironmongerydirect.co.uk/product/altro-heavy-duty-tubular-latch-128mm-case-107mm-backset-square-pvd-brass-267276

 

[elmag28]

JohnD... Thanks for identifying the lock. I didn't measure the thickness. I will take it out & measure it.
I will go through the options you mentioned & get back to you.
Many thanks